Gas Laser

Abstract

A gas laser with a discharge bore defined by a single-bore extruded ceramic discharge tube is disclosed. An outer tube is located over the discharge tube so as to define an annular space therebetween. Caps are located over both ends of the tubes and each cap is provide with at least one gas transport passage so the discharge bore and the annular space are in communication. The annular space is filled with electrically insulating, thermally conducting components such as washers, baffles and ceramic granules. When the laser is in operation the annular space serves as a gas return path so a uniform equilibrium pressure is maintained in the discharge bore. The components in the annular space inhibit the flow of electrical current in the space so all of the current flow is through the discharge bore so as to excite the gas therein. The components in the annular space also provide a thermally conductive path between the discharge tube and the outer tube to diffuse heat away from the discharge bore.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. A gas laser comprising, (a) a discharge tube with a discharge bore extending axially therethrough;   (b) laser gas in said discharge tube bore,   (c) an outer tube coextensive with and surrounding said discharge tube, and spaced away from said discharge tube so as to define an annular space therebetween from which said laser gas flows into said discharge tube bore;   (d) a first end cap coupled to one end of said discharge tube and one end of said outer tube, said end cap supporting a partially-reflecting mirror and including at least one gas transport passage between said discharge and said annular space;   (e) a second cap coupled to the ends of said discharge tube and said outer tube opposite said first cap, said end cap supporting a highly-reflecting mirror and including at least one gas transport passage between said discharge bore and said annular space; and   (f) at least one electrically insulating, thermally conducting component in said annular space extending between said discharge tube and said outer tube to provide a thermally conductive path between said discharge tube and said outer tube.   
     
     
       2. The laser of claim 1 wherein said component in said annular space comprises an electrically insulating, thermally conductive, porous fill disposed within said annular space between said discharge tube and said annular space. 
     
     
       3. The laser of claim 2 wherein said porous fill is in granular form. 
     
     
       4. The laser of claim 2 wherein said porous fill is aluminum oxide ceramic granules. 
     
     
       5. The laser of claim 2 wherein said porous fill is beryllium oxide ceramic granules. 
     
     
       6. The laser of claim 2 wherein said porous fill is sapphire granules. 
     
     
       7. The laser of claim 1 wherein at least one electrically insulating, thermally conducting baffle is discharged within said annular space between said discharge tube and said outer tube, said baffle including at least one gas transport bore that extends therethrough. 
     
     
       8. The laser of claim 7 wherein said gas transport bores extend axially through said baffles at an angle offset to the axis of said annular space. 
     
     
       9. The laser of claim 7 wherein, (a) electrically insulating, thermally conductive, porous fill is disposed in said baffle gas transport bores,   (b) whereby said laser gas flows through said porous fill in said transport bores.   
     
     
       10. The laser of claim 7 wherein said baffle is formed of aluminum oxide ceramic. 
     
     
       11. The laser of claim 7 wherein said baffle is formed of beryllium oxide ceramic. 
     
     
       12. The laser of claim 1 wherein at least one electrically insulating, thermally conducting, large washer is disposed in said annular space, said washer having an outer perimeter adjacent to said outer tube and an inner perimeter spaced away from said discharge tube. 
     
     
       13. The laser of claim 12 wherein electrically insulating, thermally conducting, porous fill is disposed in said annular space between said large washer and said discharge tube. 
     
     
       14. The laser of claim 12 wherein an electrically insulating, thermally conducting small washer is disposed in said annular space, said small washer having an inner perimeter adjacent to said discharge tube and an outer perimeter spaced away from said outer tube. 
     
     
       15. The laser of claim 14 wherein at least one of small washers is adjacent to one of said large washers. 
     
     
       16. The laser of claim 14 wherein an electrically insulating, thermally conducting porous fill is disposed in said annular space between said large washer and said discharge tube, and between said small washer and said outer tube. 
     
     
       17. The laser of claim 12 wherein said large washers are composed of aluminum oxide ceramic. 
     
     
       18. The laser of claim 12 wherein said large washers are composed of beryllium oxide ceramic. 
     
     
       19. The laser of claim 13 wherein said small washers are composed of aluminum oxide ceramic. 
     
     
       20. The laser of claim 13 wherein said small washers are composed of beryllium oxide ceramic. 
     
     
       21. The laser of claim 1 wherein porous, thermally conducting material is disposed in said annular space in at least one end adjacent to an end cap. 
     
     
       22. The laser of claim 1 wherein said first end cap includes a discharge bore concentrate with and projecting from said discharge bore, a diffusion cavity adjacent to said cap discharge bore, and said gas transport passages extending from said diffusion cavity to said annular space, said transport passages each including at least a portion that extends from said diffusion cavity at an angle offset from the axes of said discharge bores. 
     
     
       23. In a laser including a fluid lasing medium contained in a discharge tube, the improvement comprising, (a) said discharge tube being formed from a relatively thin wall extruded ceramic tube,   (b) a relatively thick wall outer tube coextensive with and surrounding said discharge tube and defining an annular space therebetween, and   (c) a porous fill material substantially completely filling said annular space,   (d) whereby the orientation of said discharge tube within said outer tube is maintained by said fill material.   
     
     
       24. A gas laser comprising, (a) a discharge tube with a discharge bore extending axially therethrough;   (b) a laser gas in said discharge tube bore,   (c) an outer tube coextensive with and surrounding said discharge tube, and spaced away from said discharge tube so as to define an annular space therebetween through which said laser gas can flow;   (d) a first end cap coupled to one end of said discharge tube and one end of said outer tube, said end cap including at least one gas transport passage between said discharge bore and said annular space;   (e) a second end cap coupled to the ends of said discharge tube and said outer tube opposite said first cap, said end cap including at least one gas transport passage between said discharge bore and said annular space; and   (f) at least one electrically insulating, thermally conducting component in said annular space extending between said discharge tube and said outer tube to provide a thermally conductive path between said discharge tube and said outer tube.   
     
     
       25. The laser of claim 24 wherein, (a) said component in said annular space comprises an electrically insulating, thermally conductive, porous fill disposed within said annular space between said discharge tube and said annular space.   (b) whereby said laser gas can flow through said porous fill.   
     
     
       26. The laser of claim 25 wherein said porous fill is in granular form. 
     
     
       27. The laser of claim 25 wherein said porous fill is aluminum oxide ceramic granules. 
     
     
       28. The laser of claim 25 wherein said porous fill is beryllium oxide ceramic granules. 
     
     
       29. The laser of claim 25 wherein said porous fill is sapphire granules.